Topic: active record

can i declare all the model class in one model class?
i have declare like following, is it possible or not? anybody know please reply

file name:some.rb
class Product < ActiveRecord::Base
    has_many :product_reviews
    has_many :product_ratings
    has_many :product_property_rule_values
    has_one :product_overall_rating
    has_many :product_dynamic_properties
    has_and_belongs_to_many :product_category
end
class ProductReview < ActiveRecord::Base
    belongs_to :products
end
class ProductRating < ActiveRecord::Base
    belongs_to :products
end
class ProductPropertyRuleValue < ActiveRecord::Base
    belongs_to :products
    belongs_to :properties
end
class ProductOverallRating < ActiveRecord::Base
    belongs_to :prodcuts
end
class ProductDynamicProperty < ActiveRecord::Base
    belongs_to :products
end
class ProductCategory < ActiveRecord::Base
    acts_as_tree :order=> "category_text"
    has_and_belongs_to_many :products
end
class Property < ActiveRecord::Base
    has_many :product_property_rule_values
end

here all the model class are seperate one i have declare all the relationship in one model can i access these classes in some other class?